Can it be used to make super-items? I'd like to have a single item containing all of https://archive.org/details/wikimediacommons (or at least groups of 12 items) so that it gets even easier to download in bulk without having to actually upload super-huge tarballs.

Would be great if it were possible to use it to group a series of audio files into a collection. For example, I use archive.org to archive the preaching at our church. I generally have submitted each message separately, but a series on a particular book of the Bible may have 30-60 messages in it. It would be great to be able to suck all of these messages together onto one page for the whole series!